The invention relates to an electric power-transmission device.
In numerous transport operations, vehicles are moved on multiple-use, level traffic surfaces. It is known from DE-A-44 46 779 that the inductive transmission of electrical power into the 100-kW range from lines laid in the transport path to the vehicles via air gaps of more than 10 cm is possible. The application spectrum for the vehicles to be supplied without contact over the transport path encompasses, for example, small-container transport for files with powers in the 100-W range, unmanned transport systems in conveyor and assembly operations in the kW range, and goods and passenger transport vehicles with powers of 10 to over 100 kW. The use of traffic surfaces or the topology of the transport path with branches and intersections does not permit power-transmission devices to be mounted above the traffic surface, or openings in the traffic surface for a sub-surface power tap. The vehicles must therefore carry their drive power along in a battery. The used transmitters have U- or E-shaped transmitter heads that include a ferrite core and the transmission line.
A further energy-transmission device is known from, for example, JP 07-067 270 A. This device comprises a primary conductor arrangement that is laid in a transport path, and includes two parallel primary conductors and a secondary winding arrangement that is electromagnetically coupled thereto and is disposed on the floor of a vehicle. The secondary winding arrangement is formed by two adjacent coils of equal width that are connected to power converters, which feed DC voltages and direct currents into a battery. In this arrangement, a differential amplifier forms the difference between the output voltages of the power converters, and the deviation of the vehicle from the center of the primary conductors is determined from this difference. There is, however, no specification for the features relating to the shape, design and placement of the conductor arrangements in the transport path and on the vehicle floor, which effect the greatest-possible magnetic coupling between the primary and secondary sides with the lowest-possible conductor inductances and the lowest-possible magnetic field intensities scattering into the environment. Rather, the figure illustrates a primary-side and secondary-side arrangement of conductors and coils having compact, square cross sections that are known to have high internal magnetic leakage fluxes and high internal inductances, which do not contribute to the magnetic coupling of the primary conductor arrangement and the secondary coil arrangement.
JP 07-297 058 discloses a power-transmission device that has three parallel primary conductors, specifically a central conductor and two outside conductors, which are laid in one plane, with the total current of an AC-voltage source flowing in one direction in the central conductor and dividing at the end of the primary conductor arrangement into two currents of equal magnitude, which flow back to the source in the two outside conductors. This conductor arrangement impedes the generation of induction currents in a conductor that is not a component of the power-transmission device. This patent application also offers no specification of the shape, design and placement of the conductor arrangements in the transport path and on the vehicle floor, which are intended to attain a large magnetic coupling between the primary and secondary sides with the lowest-possible conductor inductances and the smallest-possible magnetic fields scattering into the environment. While the figures illustrate how the magnetic flux generated by the primary conductors is conducted through the secondary-side winding arrangement comprising one or two coils by differently-shaped cores, these arrangements are, again, exclusively coil-and-conductor arrangement having a compact conductor cross section that has a high internal magnetic leakage flux and a high internal inductance, which do not contribute to the magnetic coupling of the primary conductor arrangement and the secondary coil arrangement. Furthermore, the secondary-side coil arrangements are spaced far from the primary conductor arrangement, and expand considerably in the direction perpendicular to the plane of the primary conductors, which increases the magnetic leakage flux and the inductance of the secondary-side coils without improving the magnetic coupling.
The undesired magnetic leakage fluxes of the conductor arrangements of the prior art not only increase the dimensions and the material requirement for a power-transmission device designed for a specific power, but cause an electromagnetic exposure in the area surrounding the power-transmission device, particularly in devices intended for high transmission powers. Because the magnetic field intensities of this exposure are limited by standards, a transmission device having large magnetic scatter fields can only transmit lower powers than a transmission device in which the shape, design and placement of the conductor arrangements in the transport path and on the vehicle floor keep the magnetic leakage fluxes to a minimum.
It is therefore the object of the invention to provide a power-transmission device that has the greatest-possible magnetic coupling between the primary conductor arrangement laid in a transport path and the secondary winding disposed on a vehicle floor, and in which undesired magnetic leakage fluxes and inductances are minimal.
The above object generally is accomplished according to the present invention. Advantageous embodiments and modifications of the basic invention are disclosed.
The inventive concept is an electric power-transmission device having a primary conductor arrangement comprising at least two parallel primary conductors and a secondary winding arrangement, which is electromagnetically coupled thereto, is mechanically separate from the primary conductor arrangement and can be moved in its longitudinal direction. According to the invention, the primary conductor arrangement and the secondary winding arrangement comprise flat conductors having a small thickness of a few millimeters and a large width side (bL), the width sides of the primary conductors are disposed adjacently in one plane, and the secondary winding arrangement has at least one secondary coil, which is embodied as a disk winding whose conductor width sides lie in one plane extending parallel to the plane that receives the primary conductor arrangement.
The disk winding is preferably embodied as a ring winding having two parallel, spaced winding segments, with a first winding segment being in the immediate vicinity of a first primary conductor, and a second winding segment being in the immediate vicinity of a further primary conductor, and extending parallel thereto.
In a further preferred embodiment, the primary conductors are embodied as flat conductors whose surface normals extend perpendicular to the plane that receives the secondary winding arrangement.
In a further preferred embodiment, the primary conductor arrangement comprises at least three primary conductors and the secondary winding arrangement comprises at least two secondary coils.
In a further preferred embodiment, winding segments of adjacent secondary coils are associated with a central primary conductor, or a plurality of primary conductors through which current flows in the same direction.
In a further preferred embodiment, at least one ferrite plate is associated with the secondary winding arrangement on at least the side opposite the primary conductor arrangement, and/or at least one ferrite plate is associated with the primary conductor on at least the side opposite the secondary winding arrangement.
In a further preferred embodiment, the secondary winding arrangement is disposed on a vehicle floor. It is particularly advantageous to embed the secondary winding arrangement in a casting compound.
The primary conductor arrangement is preferably immovably fixed near the surface of a transport path. It is advantageous to produce the primary conductor arrangement from litz material.
The essential features of the invention are described in detail below and illustrated in figures.